The present invention relates generally to endoscopes and, more particularly, to an improved mechanism and the like for controlling the curvature of a bendable portion at the distal end of the endoscope.
In endoscopes of the type which are adapted to be inserted into a body cavity for purposes of diagnosis, treatment, and/or operation of a digestive organ or the like, the bendable portion constituting the distal end of the flexible tubular member which has been inserted into the body cavity must be bent in a controlled manner through external manipulation of components of the endoscope. Difficulties are often encountered however, in manually inserting an endoscope into the digestive tract of a living body. These difficulties chiefly arise from the intricately twisted form of the digestive tract, for example, the large intestine. Therefore, it has hitherto been necessary to try to frequently control the direction in which the distal end portion of an endoscope, for example, a colon scope is inserted into the colon in conformity to the intricately twisted form of the colon in order to effect the smooth full insertion of said instrument. However, the above mentioned control sometimes caused the distal end portion of the endoscope to forcefully press the inner wall of the colon, thus imparting great pain to a patient, and unavoidably prolonging the time of examination.
To alleviate the causes of of pain while enabling a meaningful examination, various mechanisms for controlling the curvature of the bendable portion of the endoscope have been proposed. Many of the known curvature control mechanisms utilize an arrangement wherein a plurality of control wires extend parallel to one another from the forward bendable portion through the flexible tubular member or intermediate portion of the endoscope to a manipulator unit to which the flexible tubular member is attached. The application of a pulling or tension force on one of the control wires results in a tension-relief of another control wire so that a desired curvature of the bendable portion of the endoscope is achieved.
Such devices have also been used for the diagnosis and treatment of disorders associated with joints of the body and notably with the knee joint. For example, American Edwards Laboratories of American Hospital Supply Corporation has developed the Flexiscope.TM. System which has served to extend innovative arthroscopic techniques simply, effectively, and with minimal trauma to the patient. The Flexiscope system utilizes an integrated eyepiece with an elongated fiber optic lens system for image and illumination transmission. In brief, after an incision has been made through the skin tissues and into the portions of the joint to be viewed, a tubular introducer is inserted into the joint and attached to the outer tissues covering the joint. Thereafter, a directing cannula is inserted through the introducer into the cavity to be explored. The cannula is of a semi rigid material having a tip end deflected to a predetermined angle relative to the remainder of the cannula. The angle of deflection at the tip end is in the memory of the device such that it can be straightened for passage of the cannula through the introducer, but when the tip end of the cannula emerges from the far end of the introducer, it returns to its predetermined shape. The flexible elongated fiber optic portion of the Flexiscope system is then inserted through the directing cannula down to the tip end and necessarily follows the curvature of the tip end of the cannula. With the tip end of the cannula directed at the object to be examined, the operator of the Flexiscope system can readily view and examine that object.
Presently, a series of directing cannulas is required for purposes of diagnosis, each having a tip end deflected to a different angle of inclination with respect to the major axis of the cannula. These tip ends can typically be bent at a variety of angles between 0.degree. and 90.degree..
A drawback of this known system becomes apparent when it is desired to examine objects within the joint at different locations or positions. In that event, it is necessary to remove the fiber optic portion of the Flexiscope system as well as the particular directing cannula from the joint cavity, replacing the cannula with one having a different angled tip end, then reinserting the fiber optic portion of the Flexiscope system. This is a laborious, time consuming process which can also cause trauma to the joint structure and possibly pain to the patient.
It was with a view to continuing to use the highly successful Flexiscope system while improving control of the tip end of the fiber optics of that system that the present invention has been conceived and now reduced to practice.